Flow-through capacitors are represented in Andelman U.S. Pat. No. 5,192,432, issued Mar. 9, 1993; U.S. Pat. No. 5,196,115, issued Mar. 23, 1993; U.S. Pat. No. 5,200,068, issued Apr. 6, 1993; U.S. Pat. No. 5,360,540, issued Nov. 1, 1994; U.S. Pat. No. 5,415,768, issued May 16, 1995; U.S. Pat. No. 5,547,581, issued Aug. 20, 1996; U.S. Pat. No. 5,620,597, issued Apr. 15, 1997; U.S. Pat. No. 5,779,891, issued Jul. 14, 1998; Otowa U.S. Pat. No. 5,538,611, issued Jul. 23, 1996; Farmer U.S. Pat. No. 5,425,858, issued Jun. 20, 1995; and Benak U.S. Pat. No. 3,658,674, issued Apr. 25, 1972. These patents all describe flow-through capacitors that electrically comprise a single electric cell per cartridge holder. Scale up to larger size causes these capacitors to draw high amperage power. High amperage power requires extra thick wires and buss bars and expensive power supplies. Therefore, a need exists for a flow-through capacitor which can utilize less expensive, more economical, higher voltage, lower amperage power for a given watt rating.
The aforementioned prior art patents describe single cell capacitors with one cell per cartridge holder, utilizing multiple, parallel-connected anode and cathode layers per cell. A cell comprises at least one anode and cathode layer with an ionically conducting electrolyte that operates within the rated cell voltage. This rated voltage is usually set below the level where electrode deterioration takes place or other undesirable electrochemical reactions occur. Where multiple electrode layers exist, these layers are usually connected in parallel. In the flow-through capacitor, this electrolyte is the working fluid that is being treated. In order not to exceed the rated voltage per cell, this fluid must be electrically isolated from the fluid in any other cell. In order to electrically connect prior art capacitors in series, individual flow-through capacitor cartridge holders must be chained together. Fluid flow and electricity must be distributed equally between cells, so that the individual cell voltages do not become unbalanced. This often requires that each cell be individually monitored and controlled. For example, FIG. 15 of Andelman U.S. Pat. No. 5,799,891 pictures a flow-through capacitor system with three flow-through capacitors in individual cartridge holders. Each cartridge holder contains one cell, typically made from multiple, parallel-connected electrodes. Use of an additional cartridge holder per cell increases the cost of series-connected, flow-through capacitors that comprise multiple cells, yet are self-contained in one cartridge holder. Also, a need exists for a series-connected, flow-through capacitor that can operate at voltages higher than that of a single cell, yet within a single cartridge holder, where the individual cells are electrically isolated from one another.
Otowa U.S. Pat. No. 5,538,611 and Farmer U.S. Pat. No. 5,425,858 both utilize gaskets to isolate the fluid flow path. Otowa utilizes single electrode layers sealed by a gasket. However, Otowa does not use double-sided electrodes to provide a capacitor of enhanced voltage internal to a single cartridge holder. Farmer utilizes gaskets and many double-sided, internal electrode layers, but these layers are connected in parallel.
The invention relates to a flow-through capacitor, system and method.
It is desirable to provide a series-connected, flow-through capacitor to allow the use of more energy and cost efficient electrical power within a single, easy to manufacture cartridge.
The invention is also related to a series-connected, flow-through capacitor with multiple individual electrolyte-isolated cells and which capacitor is self-contained in a single cartridge holder.
An additional advantage of the present invention is that only the electrical leads at the either end of the electrode stack need be connected to a power supply, yet voltage may be higher than the single cell rating.
The invention comprises a flow-through capacitor for the purification of an electrolyte fluid, which capacitor includes: a cartridge holder; an inlet in the holder for a fluid to be purified; an outlet in the holder for the withdrawal of a purified fluid; a discharge outlet; and a plurality of electrolyte-isolated individual cells, each cell composed of an anode-cathode pair of electrode material in a stacked arrangement within the holder, and the individual cells are electrically connected in series.
In the present invention, the electrodes of the capacitor are series-connected, due to sealing gasket, so that the intermediate electrodes of the capacitor simultaneously comprise an anode on one side and a cathode on an other side.
The invention will be described for the purpose of illustration only in connection with certain illustrated embodiments; however, it is recognized that various changes, modifications, additions, and improvements may be made in the illustrative embodiments without departing from the spirit or scope of the invention.